At The Fork In The Road


A traveler comes to a fork in the road and does not know which way
to go to reach his destination. There are two men at the fork, one 
of whom always lies while the other always tells the truth. 

The traveler doesn't know which is which. He may ask only one 
question to find his way. What is his question and which man
does he ask? 
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Answer:
He asks either man, "If I were to ask you if this is the way I 
should go, would you say yes?" 

Solution:
He needs a question that will give him his answer no matter which
one he askes, and the one chosen fits the bill very nicely.  When
the man who is always truthful is asked this question, he will, 
of course, give the right answer. 

If, however, the man he asks is the man who always lies, that man 
will lie about the answer he would give, thus also giving the 
correct answer.